A growing number of public school administrators are capitulating to the obvious — that it is better for teenagers to get extra sleep at home than in the classroom. It’s about time.

It has taken several decades for them to come to that position although one suspects that they have known all along that starting the high school day an hour later is more suitable to teenage biological needs and enhances performance through, among other things, improved attentiveness. After all, studies over several decades have repeatedly verified this. I’ve been advocating it for that long.

A University of Minnesota study 15 or so years ago, proved fairly conclusively that just the small change to meet the sleeping habits of 13 to 18 year olds, made a difference in their learning curve. The Minnesota researchers recently followed up with a study of eight high schools in three states before and after they changed their schedules to later start times that showed marked improvement in several areas, including mental health, standardized tests, attendance and even car crash statistics.

Among the first to realize the significance of starting later were school systems in Connecticut, North Carolina, Kentucky and, of course, Minnesota. Recent converts to the idea include systems in Georgia, California, Oklahoma, and New York. A half -dozen school boards in metropolitan areas like Seattle, Montgomery County, Md., and Fairfax, Va., also are moving in that direction.

Then why has acceptance of the idea been so illusive? The answer is simple. The current model of ringing the first bell at 7:30 or even earlier in some cases better suits the parents, teachers and their bosses. In other words, this never really has been about what’s best for the students especially in a culture when both parents work, bus routes are often long and complex and after-school activities demand an early finish to the classroom day. Then there is the homework argument that if you let them come in an hour later the amount of time needed for homework is cut short on the other end.

This claim, however, has always seemed specious considering that one of the reasons for pushing back the start time is because teenagers generally stay up later. It’s a hormone thing that keeps them alert until 11 p.m. or even beyond. Shorting them on the morning side is not a good idea as most parents can tell you. But once again the daily demands of our society frequently interfere.

From my experience in raising three boys and a girl, the evidence is irrefutable. When school started later for whatever reason, the boys were much easier to deal with. Their sister had an amazing ability to get to bed earlier but all clearly performed better when they had at least seven to eight hours of sleep. When they went off to college, they scheduled their first classes of the day with that in mind.

A side benefit to the later start, according to the Minnesota study that included 9,000 students in three states, was a decline in depression, the use of alcohol, drugs and consumption of caffeine in comparison to those teenagers who had less sleep. According to the report the results were the same across the board with no difference in mental health outcomes between poor kids from the inner-city and affluent ones.

This is a nation that spends untold amounts of money on trying to find ways to improve its public schools while often ignoring the relatively simple solutions that are available. Teaching boys and girls separately for instance acknowledges what most veteran teachers at least and certainly parents understand; that the two sexes learn at a different pace and respond to different stimuli. Yet the resistance to this approach, based on a phony social equality policy and that it costs too much has stymied it for years. It is a case where separate may be more equal than not. Once again concern for the student seems not to be in the mix.

Fortunately for the teenagers who are just beginning their high school careers, the move is toward giving them a better chance for success by allowing them a crucial hour of extra slumber to meet their biological needs. If it requires some schedule juggling and rearranging of adult time, it will be well worth it. There is ample evidence of that. The benefit far outweighs other considerations.

Dan Thomasson is an op-ed columnist for McClatchy-Tribune and a former vice president of Scripps Howard Newspapers. Email at: thomassondan@aol.com.